An RBC is typically comprised of a rotating shaft to which is attached a bank, or multiple banks, of media that are then in turn rotated by the shaft. A plurality of parallel support shafts is typically employed to aid in the support of the media. The media is typically located such that about 40 percent of the media is, at any given time, immersed in the wastewater to be cleaned. As the media rotates slowly into and out of the wastewater, microorganisms attach themselves to the media, forming a biomass, and consume contaminants from the wastewater. As the media rotates into the air above the wastewater tank, the microorganisms biodegrade these contaminants, e.g., into carbon dioxide and water. Examples of technology related to the treatment of wastewater and other substances can be found with reference to the following U.S. patents listed in the Table, below, the entire disclosures of which are expressly incorporated herein by reference:
TABLEU.S. Pat. No.Inventor(s)Title1,811,181MaltbyProcess and Apparatus forTreating Sewage or OtherOrganic Matters1,947,777Huff et al.Filling Unit3,193,989SebesteAerating Waste TreatmentApparatus3,335,081El-NaggarMethod of Treatment ofSewage by Bio-Oxidationand Apparatus Therefor3,484,836WelchRotating BiologicalContactor in Sewer3,630,366JoostRotating Biological WasteTreatment System3,645,510KlugmanGrid Member and WallFormed Therefrom3,704,783AntoineApparatus for TreatingSewage3,904,525Rosenberg et al.Waste Treatment Apparatus3,915,854TorpeyWastewater Treatment4,115,268ThissenWaste Water TreatmentRotor4,137,172Sako et al.Rotating BiologicalContactor4,275,019BednarskiA Modular Heaping-TypePacking Element4,279,753Nielson et al.Wastewater TreatmentSystem Including MultipleStages of Alternate Aerobic-Anaerobic Bioreactors inSeries4,303,527Reimann et al.Surge Control in theBiological Purification ofWastewater4,345,997McConnell, Jr. et al.Media4,385,987McGinley et al.Waste Treatment Apparatus4,387,020HillFlow Control Apparatus4,399,031Imano et al.Biological Sewage TreatmentApparatus of the Rotary DiscType4,431,537HirotaRevolving Contactors for theBiological Treatment ofWaste Water4,444,658Hankes et al.Rotating BiologicalContactor Apparatus4,468,326KawertProcess in MicrobiologicalPurification and a Device andMaterials Therefor4,532,038ReidFlow Control Apparatus forAerobic Sewage Treatment4,537,678ThissenRotary Biological Contactor4,549,962KoelschRotating BiologicalContactor4,608,162Hankes et al.Rotating BiologicalContactor Apparatus4,692,241NicholsonSewage Treatment BiologicalRotors4,724,593LangMethod and Blank for theManufacture of HighEfficiency Open VolumedPacking Bodies4,737,278MillerMiniturized ModularRotating BiologicalContactor System4,999,302Kahler et al.Biological Contact GasScrubber for Waste GasPurification5,407,578NathwaniWaste Water TreatmentProcess5,419,831Fuerst et al.Rotating BiologicalAquarium Filter System5,423,978Snyder et al.Rotating Biologic AquariumFilter System5,425,874GassRotating Contactor IncludingCross Flow Media for theBiological Treatment ofWaste Water5,458,817LangFolding Packing and Methodof Manufacture5,498,376St. Louis et al.Packing5,637,263Lang et al.Multifold Packing andMethod of Forming5,679,253Fuerst et al.Rotating BiologicalAquarium Filter System5,714,097St. Louis et al.Packing5,851,636Lang et al.Ceramic Packing WithChannels for Thermal andCatalytic Beds5,853,591Snyder et al.Rotating BiologicalAquarium Filter System6,071,593Lang et al.Ceramic Packing WithChannels for Thermal andCatalytic Beds6,241,222LangStacked Packing WithSpacing Features6,403,366KimMethod and Apparatus forTreating Volatile OrganicCompounds, Odors, andBiodegradable in AirEmissions6,540,920Bounds et al.Wastewater TreatmentSystem Utilizing TextileFilter Media6,783,669Okagawa et al.Rotating Disk Type SewageTreatment Device
Another example of technology related to the treatment of wastewater and other substances can be found with reference to U.S. Patent Publication No. 20050133444, published Jun. 23, 2005, corresponding to U.S. patent application Ser. No. 10/997,117, filed Nov. 24, 2004, the entire specifications of both of which are expressly incorporated herein by reference, which describes a self-cleansing media and systems incorporating the same, for a rotating biological contactor. The media includes a disk having cones extending perpendicularly from the surface thereof. Two or more disks lock together, axially about a rotating central shaft, by connecting cones spaced throughout the disk surface having a socket at their base to receive the top of the corresponding connecting cone on the adjacent disk. The cones, by virtue of their length, space the disks a desired distance. The disks include disk segments that can link to one another along either straight and/or curved portions thereof. The geometry of the media provides free passage of the air and water during each revolution, and while the base disk slices through the air and water, the projecting cones or cylinders enter the air and water perpendicular to the direction of rotation and are washed and cleansed during each rotation.
With respect to domestic wastewater, it is mainly composed of normal household discharge. This discharge is typically characterized by peak flows in the morning hours (e.g., when people are bathing, preparing breakfast, and/or the like) and in the late afternoon hours (e.g., when people are preparing dinner, doing laundry, washing dishes, and/or the like). These peak flows are normally in the range of two to four times the average daily flows and occur for approximately two hours over the course of the day. This normally adds about twenty percent of the average daily flow to plant flow during the hours of peak flow. If these peak flows are not addressed and handled in some manner they can cause undesirable consequences for many of the wastewater treatment technologies in use today, including RBCs. Many different methods have been utilized by the wastewater treatment industry to overcome the effects of these peak flow hydraulic surges.
For example, a natural method occurs when the normal average flow is very large, or in excess of fifty million gallons per day. In systems treating these very large flows, sufficient variation in lifestyle and consequently household wastewater production occurs to smooth out the peaks and valleys in the volume curve of normal domestic flow. This produces a slightly higher design flow but because it is fairly constant it is easily handled by plant design.
However, in smaller wastewater treatment plants these hydraulic surges can and do cause upsets, overflows to the environment, and equipment failure, all of which must be addressed. The most common solution is to install an equalization tank in the fluid flow before these hydraulic surges can cause problems with the process flow. These equalization tanks, however, cause facility problems of their own. The typical location of the equalization tank in the fluid flow is after the preliminary screening and debris removal and before the primary settling system. This is raw sewage and it normally has very low oxygen content and a high level of very repugnant odors. In order to minimize the odor, many facilities utilize blowers to add oxygen in an effort to make the equalizing fluid aerobic. During part of the normal cycle this is effective, but for the rest of the cycle this causes an increased odor problem by blowing the odor into the surrounding air. In some cases hooding, collecting and treating the odor is effective, but it is costly.
In other cases, the primary settling tank doubles as an equalization tank. This is effective and enables the primary equipment to help control the odor. The main problem with this approach, however, is that the size of the primary tank must be increased by at least twenty percent and the volume of flow continuing into the plant flow must not exceed plant design flow. This flow transfer problem is hampered by the variations in fluid surface due to the variation in flow. Adjusting this variation in flow can be accomplished in many ways but is costly, and typically requires a lot of operation and monitoring man-hours as well as adding to the maintenance costs.
Therefore, there exists a need for new and improved wastewater treatment systems, especially those that employ rotating biological contactors and the like, that overcome at least one of the aforementioned problems.